1. Field of the Invention
The present invention relates to systems and methods for electromagnetic waveguides, and in particular to systems and methods for switchable electromagnetic waveguides in spacecraft.
2. Description of the Related Art
In spacecraft applications, the payload architecture may comprise Traveling Wave Tube Amplifiers (TWTAs) interconnected in redundancy rings to improve the overall system reliability. The redundancy rings allow a changeover of TWTAs without a service interruption. Switchable waveguides may be used in the design of such redundancy rings to switch the TWTA connections.
One such switchable waveguide is a T switch. When engaged, a T switch opens two straight waveguide paths which cross and connect pairs of opposite ports. Using a T switch, a redundant TWTA downstream can be switched into service without interfering with other paths in the power circuit. Known coaxial T switches are not capable of handling high power as hollow waveguides. Furthermore, high power coaxial T switches cannot be made as compactly as hollow waveguide switches.
Another kind of switchable waveguide is an R switch. R switches include a single straight waveguide path and two bypass waveguide paths. Either the straight waveguide or the bypass waveguides may be engaged at any time.
Furthermore, in the design of spacecraft, there are certain constant desirable objectives, which tend to vary only in emphasis for any particular application. These include reducing the mass and size of spacecraft components, reducing the time required to build components, improving the manufacturability, and of course, reducing component cost.
There is a need in the art for smaller, lighter, simpler and cheaper devices and methods for switching and combining electromagnetic signals. Particularly, there is a need for a switch combining the functionality of both a T switch and an R switch in a single compact device.
The present invention satisfies these needs.
To address the requirements described above, the present invention discloses an apparatus and method for switching electromagnetic radiation conducted through waveguides that is lighter, simpler and less costly than prior art devices.
A waveguide switch of the present invention comprises a housing having a first, second, third and fourth housing port and a waveguide rotor, having a first and second rotary position. The waveguide rotor includes a first T waveguide, having a first and second T port, for connecting the first and fourth housing ports in the first rotary position, a second T waveguide having a third and fourth T port, for connecting the second and third housing ports in the first rotary position and a bypass waveguide, having a first and second bypass port, for connecting the first and second housing ports in the second rotary position. The first and second rotary positions are alternately selectable by rotating the waveguide rotor.
A method of switching waveguides of the present invention comprises rotating a waveguide rotor including a first T waveguide having a first and second T port, a second T waveguide having a third and fourth T port and a bypass waveguide having a first and second bypass port, to a first rotary position in a housing including a first, second, third and fourth housing port, whereby the first and second T ports connect the first and fourth housing ports and the third and fourth T ports connect the second and third housing ports. And rotating the waveguide rotor to a second rotary position, whereby the first and second bypass ports connect the first and second housing ports.
The H-plane offset waveguide transition of the present invention allows a ridged guide with a width of approximately xc2xd the standard xe2x80x9caxe2x80x9d dimension to connect to a transition step, while offset completely to one side. The short wall of the ridged guide is approximately centered when mated to the transition step. The mirror image configuration has the ridged waveguide slid completely over to the other edge of the transition step. Effectively, two different waveguides on two different planes in a rotor can be switched to a common housing port.
One embodiment of the present invention uses the H-plane offset waveguide transition to combine the functionality of a T switch and an R switch in a single compact switch. The three standard paths of an R switch waveguide layout in a waveguide rotor, a straight waveguide (hereinafter referred to as a xe2x80x9cT waveguidexe2x80x9d) and two bypass waveguides, are disposed on a first plane in the rotor. When rotated into position, they connect to the first section of the vertically positioned transformer openings in the housing, the housing ports.
The final crossed connection required for the T switch function, via a second T waveguide, is disposed on a plane below the standard R switch configuration and substantially orthogonal to the other T waveguide. The second T waveguide is also double-ridged. This entire configuration fits into the same compact rotor volume presently used in the standard R switch. When rotated into position, this double-ridged T waveguide connects to the second section of the housing ports.
The H-plane offset transitions allow lighter, simpler and more inexpensive devices and methods for switching and combining electromagnetic signals than presently known in the art. Combining these functions in a single unit reduces the switch mass as well as the harness and interconnecting waveguide lengths.